Temperature and Viscosity Dependence of Gold Nanodot Luminescence

Strong chelation by ligands is essential for the stabilization of gold clusters used to obtain stable gold nanodots. Higher viscosity and lower temperature increase the emission intensity and blueshift the emission wavelength of nanodots, as observed in rigid environments. This indicates that the gold nanodot may consist of a flexible core structure. The strong dependence of nanodot luminescence on the rigidity of the medium suggests that the luminescence quantum yield of gold nanodots can be further improved when a rigid framework is applied for the stabilization of gold nanodots. Gold nanodots can potentially act as sensors for the temperature and viscosity of a medium. Well-designed short peptides not only impart extraordinary stability to gold nanodots in cell culture media, but also assist them in approaching cell surfaces for efficient cellular staining. Interestingly, gold nanodots regain temperature sensitivity upon binding to the cell surface, which is useful for increasing the signal-to-noise ratio.